Recently, there is growing interest in mobile devices, such as a wearable device worn on a part of a body and a gripped and used smart phone, and as a representative example of the mobile device, product development for a smart watch is actively proceeding. The smart watch is generally worn on a part, that is, a wrist, of a body of a user and includes a display to provide the user with various information. Since the display of the smart watch has a small display area among the mobile devices including a smart phone, it is not easy for a user to input various input signals by using a keyboard, thereby degrading usability and utility of the smart watch.
Further, recently, there is an increase in a wearable device which does not include a display and is worn on a part of a body of a user, and transmits a detected bio-signal of the user or a signal for a movement of the user to a mobile device, such as a smart phone. The wearable device detects a movement of a body by using an image sensor, an accelerator sensor, a gyro sensor, and the like, but when the foregoing sensors are used, complexity and volume of the wearable device are increased and manufacturing cost of the wearable device is increased. Particularly, it is difficult to precisely detect and determine an elaborate shape change and movement of a wearing portion, applied force, or a rubbing motion.
In relation to a wearable device which does not include a display, Korean Patent Application Laid-Open No. 10-2010-0072377 discloses an input device including an adaptive material to be disposed on a skin of a user, but a component, such as a substrate and a cover, configuring an entire shape is required in the sense that an elastic conductor for addressing and a plurality of sensor arrays for detecting a gesture of a user need to be used, so that complexity of the wearable device is increased and cost of the wearable device is also increased.
Further, a movement of a wearing portion is different for each user of the wearable device, so that in an existing wearable device and the related published technologies, it may be difficult for different users to provide the wearable device with the same input signal by using movements of the wearing portions. Further, different signals provided by different users are set and linked by the same user interface (UI) and display function, so that it may be difficult for a plurality of users to use the functions by the same method.